Water craft

Abstract

A water craft (77) is disclosed which includes a chassis portion (78), at least four water engaging means (30, 34, 38, 42) and interconnecting means (94, 96, 98, 100, 102, 104, 106, 108, 110, 112, 114, 116, 118, 120, 122, 124, 126, 128, 130, 132). Each water engaging means is connected to the chassis portion (78) and is moveable in a substantially vertical direction relative to the chassis portion (78), and the interconnection means is arranged to functionally link the at least four water engaging means (30, 34, 38, 42) such that during use the chassis portion is encouraged to maintain an orientation which is substantially constant relative to the average plane of the water surface, even when the water surface is undulating and the water engaging means (30, 34, 38, 42) are not all disposed in the same plane.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a water craft and, in particular, to displacement-type water craft and planing-type water craft. BACKGROUND OF THE INVENTION [0002] It is known to provide a displacement-type water craft which operates such that as the water craft moves through the water a mass of water is displaced from a front portion to a rear portion of the water craft. [0003] At relatively low speed, the water craft is capable of moving relatively efficiently through a body of water. However, when the water craft moves relatively quickly through a body of water, the rate at which water is required to be displaced consequently increases which causes significant turbulence and a consequent loss of efficiency. This effect is increased when waves are encountered by the water craft since the water craft will cut relatively deep into the body of water when the water craft passes through a wave crest. [0004] Furthermore, displacement-type water craft also ...

AI Technical Summary

Benefits of technology

[0034] Preferably, at least one of the water engaging means includes an underside surface arranged to contact the water surface during use, the underside surface being contoured so as to restrict side slippage of the water craft during use.

Problems solved by technology

However, when the water craft moves relatively quickly through a body of water, the rate at which water is required to be displaced consequently increases which causes significant turbulence and a consequent loss of efficiency.

Furthermore, displacement-type water craft also tend to provide a passenger with an uncomfortable ride and an increased risk of sea sickness since the body of the water craft generally follows the surface of the water.

However, if the surface of the body of water is not relatively flat, an uncomfortable jarring motion occurs as a result of heavy impact between the water craft and each successive wave front.

In relatively rough water, such planing-type water craft are unable to achieve planing speed and are compelled to move relatively slowly and inefficiently as displacement-type water craft.

However, such multi hull-type water craft are prone to accident because they are of rigid construction; in some circumstances, for example in relatively rough conditions, at least one hull lifts from the water surface while the other hull(s) become submerged.

As a consequence, extreme forces are localised within parts of the structure which can cause the craft to break or capsize.

Since the wings are completely submerged and cut through the water rather than travelling on the surface of the water, hydrofoil-type water craft require considerable engine power to raise the or each hull out of the body of water during use.

In addition, the drag caused by the submerged wings causes the water craft to be very inefficient when moving slowly.

Hydrofoil-type water craft are also unable to operate in relatively shallow waters as the wings and engine propellers tend to extend a few metres below the water surface when the water craft is moving slowly or is at rest.

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